chore: add a sync-repo-settings file (googleapis#98)

Author: software-dov

.github/sync-repo-settings.yaml

@@ -0,0 +1,16 @@
+rebaseMergeAllowed: true
+squashMergeAllowed: true
+mergeCommitAllowed: false
+branchProtectionRules:
+- pattern: master
+  isAdminEnforced: true
+  requiredApprovingReviewCount: 1
+  requiresCodeOwnerReviews: true
+  requiresStrictStatusChecks: true
+permissionRules:
+  - team: actools-python
+    permission: admin
+  - team: actools
+    permission: admin
+  - team: yoshi-python
+    permission: push